In the prior art, U.S. Pat. No. 3,737,835 discloses such an electric plug, which is provided with a manually actuated, self-triggering ejection mechanism. In this known ejection mechanism, actuation is via a rotatably mounted element which is circumferentially held on the plug housing in the region of the tube or cable entry and which retains by springs in the housing in a push-out means biased by a spring. When the rotatable element is operated by hand, the biased push-out means is released and ejects the plug from the outlet. When placing the plug back into the outlet, the spring of the push-out means is tensioned again, whereupon the spring-biased rotatable means locks the biased push-out means in position again.
U.S. Pat. No. 5,480,313 discloses an embodiment of a plug ejection mechanism, which is similar, but different in design. It is a particular feature of this embodiment that the housing of the plug is formed by a rotatable sleeve which has spiral grooves on the inside to provide a connecting link guide for the ejection means, which are in the form of sliders disposed laterally in the plug-in member. The sleeve rotatably mounted on the plug cooperates with a radially acting spiral spring which is located in the plug and released via the strain relief device of the cable when a pulling force acts on the cable. Thus, the strain relief device itself constitutes the triggering means which releases the biased, rotatably mounted sleeve, so that the ejection means (here the sliders) are moved toward the outlet along a restricted path in the sleeve, thus causing the plug to be released.